2,117 research outputs found

    A tool for sustainability impact assessment (ToSIA)of forest-wood chains linked with a database of sustainability indicators collected within the EFORWOOD project

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    Within the EFORWOOD project new approaches to assess the sustainability impacts of forest-wood chains (FWC) using indicators of environmental, social and economic sustainability were developed

    Assessing pollinator habitat suitability considering ecosystem condition in the Hannover Region, Germany

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    Context: Habitat suitability for pollinator species is an important indicator for pollination ecosystem service potential, i.e. for biodiversity and crop provision. Modelling habitat suitability using an expert- and process-based models such as ESTIMAP-pollination is a common and accepted approach to spatially analyse pollination service potential and to make recommendations for planning. Objectives: However, the suitability as a pollinator habitat depends not only on the land use type. It is also important to consider the condition of the habitat. For this reason, ecosystem condition information was used as a parameter for ESTIMAP modelling for the first time. Ecosystem condition data was used besides the commonly (in ESTIMAP) used information from expert assessments and from land use data. Methods: As parameters for ecosystem condition, the management intensity in agro ecosystems, the management of forests and the proportion of green space in urban areas were included and affected the modelled habitat suitability for wild bees. Results: Not all ecosystem types of the region were equally affected by the inclusion of the ecosystem condition parameter in the model. The most affected types were agricultural areas, such as arable and horticultural biotopes, whose suitability values decreased by 25.7%. As a result, areas with low suitability account for 41% of the region and 76.6% of the agro ecosystems. In forest, shrubs and woody plants land use types, the suitability decreased respectively by 4.3 and 6%. On the other hand, urban ecosystems in the city of Hannover were characterised by relatively good habitat suitabilities, especially in the proximity of wide urban forests. In 3.4% of the agricultural land, measures to support pollinators have been established. 1.6% of these measures are located in areas with low suitability. Conclusions: The results show that ecosystem condition is, in addition to land use type, an important parameter to indicate habitat suitability for pollinators. Especially for ecosystem types with varying habitat suitabilities, such as agro ecosystems, the implementation of ecosystem condition parameters is recommendable. However, the selection of suitable ecosystem condition indicators still requires further research and concise definitions

    Ethics and Military Practice

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    Democratic societies expect their armed forces to act in a morally responsible way, which seems a fair expectation given the fact that they entrust their armed forces with the monopoly of violence. However, this is not as straightforward and unambiguous as it sounds. Present-day military practices show that political assignments, social and cultural contexts, innovative technologies and organisational structures, present military personnel with questions and dilemma’s that can have far-reaching consequences for all involved – not in the last place for the soldiers themselves. A thorough training and education, in which critical thinking is developed and stimulated, seems therefore a necessary condition for morally responsible behaviour. This book aims to contribute to this form of ‘reflective practitioning’ in military practice

    Effects of St. John's wort on irinotecan metabolism

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    St. John's wort (SJW), a widely used herbal product, has been implicated in drug interactions resulting from the induced expression of the cytochrome P450 CYP3A4 isoform. In this study, we determined the effect of SJW on the metabolism of irinotecan, a pro-drug of SN-38 and a known substrate for CYP3A4. Five cancer patients were treated with irinotecan (350 mg/m(2), intravenously) in the presence and absence of SJW (900 mg daily, orally for 18 days) in an unblinded, randomized crossover study design. The plasma levels of the active metabolite SN-38 decreased by 42% (95% confidence interval [CI] = 14% to 70%) following SJW cotreatment with 1.0 micro M x h (95% CI = 0.34 micro M x h to 1.7 micro M x h) versus 1.7 micro M x h (95% CI = 0.83 micro M x h to 2.6 micro M x h) (P =.033, two-sided paired Student's t test). Consequently, the degree of myelosuppression was substantially worse in the absence of SJW. These findings indicate that patients on irinotecan treatment should refrain from taking SJW because plasma levels of SN-38 were dramatically reduced, which may have a deleterious impact on treatment outcome

    Determination of irinotecan (CPT-11) and its active metabolite SN-38 in human plasma by reversed-phase high-performance liquid chromatography with fluorescence detection

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    Sensitive high-performance liquid chromatographic assays have been developed to determine the levels of the lactone and lactone plus carboxylate (total) forms of the antitumor agent irinotecan (CPT-11) and its active metabolite SN-38, in human plasma. The related compound camptothecin was used as the internal standard. The selective sample pretreatment for the lactone forms involved a single solvent extraction with acetonitrile-n-butyl chloride (1:4, v/v), whereas the sample clean-up for the total forms was a simple protein precipitation with aqueous perchloric acid-methanol (1:1, v/v), which results in the conversion of the carboxylate to the lactone forms. Chromatography was carried out on a Hypersil ODS column, with detection performed fluorimetrically. The methods have been validated, and stability tests under various conditions have been performed. The lower limits of quantitation are 0.5 and 2.0 ng/ml for the lactone and total forms, respectively. The assays have been used in a single pharmacokinetic experiment in a patient to investigate the applicability of the method in vivo

    Factors involved in prolongation of the terminal disposition phase of SN-38: clinical and experimental studies

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    The active metabolite of irinotecan (CPT-11), 7-ethyl-10-hydroxycamptothecin (SN-38), is either formed through enzymatic cleavage of CPT-11 by carboxyl esterases (CEs) or through cytochrome P-450 3A-mediated oxidation to 7-ethyl-10-[4-(1-piperidino)-1-amino] carbonyloxycamptothecin (NPC) and a subsequent conversion by CE. In the liver, SN-38 is glucuronidated (SN-38G) by UGT1A1, which also conjugates bilirubin. Fourteen patients were treated with 350 mg/m2 CPT-11, and we performed pharmacokinetic analysis during a 500-h collection period. The half-life and area under the plasma concentration-time curve of SN-38 were 47+/-7.9 h and 2.0+/-0.79 microM x h, respectively, both representing a 2-fold increase as compared with earlier reported estimates (A. Sparreboom et al, Clin. Cancer Res., 4: 2747-2754, 1998). As an explanation for this phenomenon, we noted substantial formation of SN-38 from CPT-11 and NPC by plasma CE, consistent with the low circulating levels of NPC observed. In addition, transport studies in Caco-2 monolayers indicated that nonglucuronidated SN-38 could cross the membrane from apical to basolateral, indicating the potential for recirculation processes that can prolong circulation times. Interestingly, individual levels of fecal beta-glucuronidase, which is known to mediate SN-38G hydrolysis, were not related to any of the SN-38 kinetic parameters (r = 0.09; P = 0.26), suggesting that interindividual variation in this enzyme is unimportant in explaining SN-38 pharmacokinetic variability. We have also found, in contrast to earlier data, that SN-38G/SN-38 plasma concentration ratios decrease over time from approximately 7 (up to 50 h) to approximately 1 (at 500 h). This decrease could be explained by the fact that glucuronidation of SN-38 and bilirubin is increasingly competitive at lower drug levels. In addition, no evidence was found for SN-38G transport through the Caco-2 cells. Our findings indicate that until now the circulation time of SN-38 has been underestimated. This is of crucial importance to our understanding of the clinical action of CPT-11 and for future pharmacokinetic/pharmacodynamic relationships

    Measurement of fraction unbound paclitaxel in human plasma

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    The clinical pharmacokinetic behavior of paclitaxel (Taxol) is distinctly nonlinear, with disproportional increases in systemic exposure with an increase in dose. We have recently shown that Cremophor EL, the formulation vehicle used for i.v. administration of paclitaxel, alters drug distribution as a result of micellar entrapment of paclitaxel, and we speculated that the free drug fraction (fu) is dependent on dose and time-varying concentrations of Cremophor EL in the central plasma compartment. To test this hypothesis, a reproducible equilibrium dialysis method has been developed for the measurement of paclitaxel fu in plasma. Equilibrium dialysis was performed at 37 degrees C in a humidified atmosphere of 5% CO(2) using 2.0-ml polypropylene test tubes. Experiments were carried out with 260-microliter aliquots of plasma containing a tracer amount of [G-(3)H]paclitaxel with high-specific activity against an equal volume of 0.01 M phosphate buffer (pH 7.4). Drug concentrations were measured by both reversed-phase HPLC and liquid scintillation counting. Using this method, fu has been measured in three patients receiving three consecutive 3-weekly courses of paclitaxel at dose levels of 135, 175, and 225 mg/m(2) and found to range between 0.036 and 0.079. The method was also used to define concentration-time profiles of unbound drug, estimated from the product of the total plasma concentration and fu

    Genetically Determined High Levels of Iron Parameters Are Protective for Coronary Artery Disease

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    The observation that premenopausal women have a relatively low incidence of heart disease led in the nineteen eighties to the hypothesis that iron deficiency protects against heart diseases. These early observations were followed-up by conflicting epidemiological data. To confer causal relationships from epidemiological data is challenging as results can be influenced by residual confounding or reverse causation. For bias reduction, an alternative analysis strategy utilizing single-nucleotide polymorphisms (SNPs) as instrumental variables (Mendelian Randomization) has been developed. A recent study using 3 iron status associated SNPs suggested a protective effect of a higher iron status on the development of CAD.3 With a larger set of SNPs covering different components of iron metabolism, we aimed to provide a reliable answer to this lingering question

    Strongyloidiasis - the most neglected of the neglected tropical diseases?

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    Soil-transmitted helminths of the genus Strongyloides (S. fuelleborni and the more prevalent S. stercoralis) are currently believed to infect an estimated 30-100 million people worldwide. The health consequences of S. stercoralis infections range from asymptomatic light infections to chronic symptomatic strongyloidiasis. Uncontrolled multiplication of the parasite (hyperinfection) and potentially life-threatening dissemination of larvae to all internal organs is found among individuals with compromised immune system functions. This paper provides an overview of the current state of the art in relation to diagnostic methods for detecting the infection, the morbidity caused by the infection and the recommended treatment. It further discusses some of the reasons why this infection is so neglected and the consequence of this for the estimated global prevalence. The paper finally points to the gaps in our knowledge and future research needs related to this infection. As Strongyloides infections have the potential to develop into severe disease in certain population subgroups, untreated infections could cause serious problems in the community. Therefore, we need to carefully investigate this parasite in order to develop and implement effective control programme
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